Unforced variations: Jan 2011

After perusing the comments and suggestions made last week, we are going to try a new approach to dealing with comment thread disruptions. We are going to try and ensure that there is always an open thread for off-topic questions and discussions. They will be called (as this one) “Unforced Variation: [current month]” and we will try and move all off-topic comments on other threads to these threads. So if your comment seems to disappear from one thread, look for it here.

Additionally, we will institute a thread for all the troll-like comments to be called “The Bore Hole” (apologies to any actual borehole specialists) that won’t allow discussion, but will serve to show how silly and repetitive some of the nonsense that we have been moderating out is. (Note that truly offensive posts will still get deleted). If you think you’ve ended up there by mistake, please let us know.

With no further ado, please talk about anything climate science related you like.

We have a controversy in Sweden over a citation of James Hansen. “Within 15 years, global temperatures will rise to a level which hasn’t existed on earth for 100,000 years”. “Hansen said the average U.S. temperature had risen from one to two degrees since 1958 and is predicted to increase an additional 3 or 4 degrees sometime between 2010 and 2020″.”

Now does any one know what the models said would happen to global warming if we would continue using chloroflourocarbons?

[Response: Not a great piece of journalism there. No indication of even whether the temperatures are in C or F (likely to be F, given the source). The reference to 100,000 years is the same reference as was used in Hansen et al (1988) based on estimates of what the Eemian temperatures may have been. However, given that this is related to Senate or Congressional testimony, the text of the actual evidence is likely available in a library somewhere. I doubt very much that the testimony would be very different from what is in the papers, so I conclude that the journalist is probably guilty of dropping the caveats, the range and the context for the numbers they are writing about. – gavin]

Gavin,
I am surprised that you thought I was talking about a linear extrapolation. My comment in #140 is clearly logarithmic.
David,
A temperature lag could result in some of the higher predicted future temperatures (>2C). However, this is just speculation at this point, and in view of the recent cooling, looks less likely.

Climate models indicate that global mean temperature should increase 3±1.5°C if atmospheric CO is doubled. A broad range of empirical evidence, ranging from the climate on other planets to paleoclimate and recent climate trends on the earth, is consistent with the climate sensitivities indicated by the climate models. After reviewing the evidence, we conclude that there is strong evidence that a doubling of atmospheric CO2 will lead to a global climate warming of at least 1.5°C. Such an increase will correspond to a climate state near or beyond the range of human experience.

The time required to reach an effective doubling of atmospheric CO is reduced by trace gases such as methane and the cholorofluorocarbons, which have begun to increase at substantial rates during the past two decades. The contribution of trace gases to the atmospheric greenhouse effect is now comparable to that of CO2. If current trends of atmospheric composition continue, effective doubling of CO2 will occur in several decades. Based on the consensus estimate for climate sensitivity, it appears likely that substantial climate change due to the greenhouse warming will become apparent during the next 1-2 decades”

[Response: I’m starting to appreciate these delphic offerings. There is a certain poetry to them. Unfortunately they have roughly the same track record of correctness as the original oracle. Temperature change since 1984 is almost 0.5ºC (0.18/0.19ºC/dec), significant increases in water vapour, big decreases in summer sea ice, net loss of glacier ice across the world…. no, nothing to see there. – gavin]

[Response: Please stop blurting out statements for which you have no evidence and provide no defense. That got old a while back–like when you first showed up here.–Jim]

If you have access to the WSJ, there is a story on page 1 this morning about the world harvest … basically, it’s less than was projected, and the concerns around that. It seemed like it would be a relevant data point for your research.

It’s really funny how one month of reduced temperatures instantly starts the “it’s not warming” chant, despite what we’ve just seen in the past year (during a quiet sun, a very strong La Nina, and a below-zero phase of the PDO). And even then, the December temp (based on UAH TLT data) is exactly average for the 1979-2009 period, which means equal to the level of warming achieved by 1993… and that during a month depressed by the greatest one month SOI value since 1973 (and the next biggies before that? 1917 and 1904).

Some people won’t accept the observations until the rubber tires on their SUVs start to melt on the pavement (and even then it will obviously have been caused by UHI).

Gavin,
The figure I showed in my last post was for the GISS dataset which shows marginal warming, 0.003C / yr, compared to the CRU data which showed similar cooling. It is baffling to me how anyone can look at either graph and conclude that warming has occurred since 2002. Granted this is a short time-frame, but the graph is in agreement with the recent statement by prof. Latif that we can experience a “lack of warming” during the next two decades.

[Response: I’m not sure how many more times I’m inclined to point out, again, that people like yourself, who think anything interesting can be said about global warming on the basis of short term trends, are just fooling themselves, but here goes: People who think anything interesting can be said about global warming on the basis of short term trends are just fooling themselves. As for Latif’s statement, that was based on the Keenlyside et al study, which, it can charitably be said, is not wearing well. Please try and talk about something more interesting. – gavin]

Nick,
I was actually referring to his response about the temperature trend being negative since 2002.

CTG,
I guess you do not understand a logarithmic increase either. I am referring to a 34% increase from the higher value, not the original. Two compounded 34% increases would result in an 80% increase over the original. Atmospheric CO2 increased 34% from 290 ppm to 390 ppm (100 ppm) from 1880-2010. An additional 34% increase amount to 133 ppm over the present day value. Is it clearer now?

Dan H. — 13 Jan 2011 @ 8:22 AM:
“Gavin,
I am surprised that you thought I was talking about a linear extrapolation. My comment in #140 is clearly logarithmic.”

The (obvious) point of Gavin’s comment was that using a simple extrapolation is hopelessly naive (and you are, in fact, doing a linear extrapolation of log transformed data). We have a lot of additional information we can use to refine the model beyond simple linear (or logarithmic, if you prefer) extrapolation.

“David,
A temperature lag could result in some of the higher predicted future temperatures (>2C). However, this is just speculation at this point, and in view of the recent cooling, looks less likely.”

I’ll do you the favor of ignoring your comment about recent cooling and focus instead on the first half of this. First, given that the most likely temp change per doubling is thought to be 3C, the “higher” predictions would be rather higher than your “2C”. Second, to say that this is “just speculation” is to ignore physics. You seem more comfortable with simple statistical models, which might be fine in some settings. To think that they are sufficient for climate is ludicrous.

Martin,
If a doubling of CO2 leads to a 3C temperature increase, then why do you think that a 34% increase resulting in a temperature rise of less than 2C is ludicrous? If order for a 34% increase in CO2 to yield a temperature rise in excess of 2C, the climate sensitivity would need to be 5C/doubling. Or are you “speculating” that the climate sensitivity is indeed that high? If so, what physics are you using in making that determination?

For Dan H. — 13 Jan 2011 @ 3:55 PM
I said that using your simplistic extrapolation was ludicrous, not the sensitivity value.

Also, it was not obvious from your post (#153) that the “>2C” sensitivity was for a 34% increase in CO2, since everyone talks about sensitivity per doubling. As such, I don’t believe I have to site any special physics to justify the 3C per doubling that I believe is the consensus figure.

I would suggest that it is incumbent upon you, who posits a much lower climate sensitivity than do those people who actually study the subject, to justify your figure with actual physics rather than naive extrapolation. I await this with baited breath.

Secular Animist:
“…assertions which they know to be untrue.”
I have a horrible feeling that many of them don’t know this at all: they think that there is a difference of opinion, and that all opinions are valid. Who need to pay shills when you’ve got postmodern claptrap on your side?

Question – what’s the evidence that the climate disruptions last summer (Moscow, Pakistan) – and perhaps also now – could stem from jet stream alteration by the solar minimum (Haigh, second-hand), rather than from Arctic sea ice loss?
(Has this been addressed? (what keywords should I search for?)
It was brought up on a local radio show and if it’s off in the weeds, I’d like to know.)

Re ccpo – the original question refered to Earth turning into Venus (likely in the deep geological future, but not from AGW now so far as I know). We could imagine the “The Day After Tomorrow” scenario may also come up (some things nominally correct but blown out of proportion; physically implausable storms (how low would the central pressure have to get?) and cold. In comparison to the Younger Dryas, we have less ice to melt in the Northern Hemisphere and it’s in different places).

Venus-like or not is irrelevant. One can only die once, and massive disruptions to BAU will come long before we reach Venus’ conditions. However, we can, and are, push the planet well beyond what civilization developed in. Entirely possible, ane, imo, probable at this point. The combination of burning another trillion barrels of oil (@ 100ppm CO2) and coal (@200 ppm? More?), natural gas (50ppm?) and, say, half the permafrost (@400 ppm?) and the Siberian clathrates (another 400+ ppm?) gets us into feedback territories that take us far enough towards Venusian conditions to make the difference a distinction without a difference.

123
Didactylos says:
12 Jan 2011 at 12:54 AM

ccpo: You said “it is impossible to be alarmist about climate changes”. I suppose you didn’t get into the subject of misinformation, but your comments were easily interpreted as the “any exaggeration is justified” canard.

Thank you for clarifying.

Sure. But we may disagree after all. I’ve never been able to track it down again, but I remember reading about a European ice sheet, now long gone, but that evidence suggests disintegrated in a decades to century time frame.

Just as virtually everything being measured is way ahead of schedule, at least as laid out in the first four IPCC reports, other accelerations cannot be ruled out. Insurance is not for the fat middle of the Bell curve, but for the long tail events or Black Swans. I called at least a meter rise back in ’07, after all, and now that is at the low end of projections.

The wobbles are getting pronounced, if you ask me. I think 6C sensitivity is probably right, all feedbacks included. One meter would be darned lucky at this point.

#140 (Dan H):
I seem to remember reading on some climate realist sites about a year ago that Climategate proved the CRU data to be rather inaccurate, so it probably best to use one of the other datasets in your example.

Any head shrinks out there that can work out what is going on in this persons brain?

from a skeptics-blog forum;

The way climate sceptics are treated is insulting and arrogant. We have maintained the same position since this whole issue began. In fact, I resented being called a sceptic because that gave the impression I did not believe in climate change. The sceptics used climate change in relation to their beliefs for a long time before the pro-warmers, because that was relative to our beliefs, as global warming was an alarmist term.

I have never participated in alarmism, scare mongering or brainwashing on my beliefs, which I base on history and cyclic weather events. My position has never changed.

I am not a denialist, nor am I a denier, as I believe in climate change.

What does make me angry though is how pro-warmers continue to presume I don’t accept climate change, and continue their argument in this fashion. They really do not understand what a sceptic is so how can they rationally argue their case against we sceptics, when the most basic information is ignored?

If you want to argue a case, don’t you need to inform yourself of basic details, and why you disagree on these details? Once you have this knowledge, then and only then can you understand where the other person may be coming from? As it is, we are treated with ignorance, intimidation, and rarely have our views printed in the media. We have been forced to the sidelines throughout the years with this argument.

We become frustrated and angry to continually have our views twisted to suit an argument, or insults issued regarding links or the authors. Worse to be told we don’t believe in climate change.

I’m sick of it. Get out of our faces, pro-warmers and let us be treated equally.

A study published in Geophysical Research Letters (subs. req’d) looked at temperature and atmospheric changes during the Middle Ages. This 2006 study found that the effect of amplifying feedbacks in the climate system –where global warming boosts atmospheric CO2 levels – “will promote warming by an extra 15-78% on a century-scale” compared to typical estimates by the U.N.’s Intergovernmental Panel on Climate Change. The study notes these results may even be “conservative” because they ignore other greenhouse gases such as methane, whose levels will likely be boosted as temperatures warm.

A second study, published in Geophysical Research Letters, “Missing feedbacks, asymmetric uncertainties, and the underestimation of future warming” (subs. req’d), looked at temperature and atmospheric changes during the past 400,000 years. This study found evidence for significant increases in both CO2 and methane (CH4) levels as temperatures rise. The conclusion: If our current climate models correctly accounted for such “missing feedbacks,” then “we would be predicting a significantly greater increase in global warming than is currently forecast over the next century and beyond”– as much as 1.5 °C warmer this century alone.

Much to quote, and several scary studies I’d not come across before. Densely populated with info.

Is long-term climate sensitivity 3C? Not a snowball’s chance in Hades.

I agree ccpo. I do not think the sensitivity is anywhere near that high.
The ice core data all show a significant CO2 rise following temperature increases, but the lag time is rather large.
Why all the hoopla about one year? I seem to remember everyone dismissing the rather cool 2009 as being “just one year.”

Actually, Dan, it was 2008, not 2009, that was the “rather cool year.” 2009 was the 6th-warmest year on record, with an anomaly of .56C–2010 and 2005 are first with .62.

And it wasn’t the mainstream that made the hoopla. If it weren’t for the constant necessity of responding to Big Lie attacks that deny the most basic aspects of our current situation–“it stopped warming,” “CO2 doesn’t warm,” “it won’t be that bad,” and even “God will protect us”–see Congressman John Shimkus–it would be a hell of a lot easier to have a sensible conversation about what’s really happening, and what to do about it.

For example, the mainstream focuses on long-term terms that are statistically significant, as opposed to cherry-picked periods such as 2002-present.

ccpo: Those may seem scary, but they still seem to be safely within the envelope of IPCC forecasts. And 15-78%? Uncertainty much? It is true that we are dealing with asymmetric uncertainties, but that doesn’t change our best estimate, based on many different methodologies.

I really don’t understand the arguments that the actual climate sensitivity is likely to lie in the least likely high range any more than I understand those repeated claims we hear that the sensitivity is most likely to be in the least likely low range.

That’s just not how mathematics work. The likely range is 2-4 degrees, and the most likely value is 3 degrees. Lower and higher vales are not ruled out, but they are not likely, and they are emphatically not the most likely.

Highly uncertain paleoclimate studies don’t exactly narrow our understanding of climate sensitivity. I believe taking only the high estimate from such studies is unjustified, since in reality, the wide spread simply confirms that the true value is likely to be in the narrower range given by more concrete studies.

ccpo, please also note that Hansen is *not* arguing that Charney sensitivity is 6 degrees. That would be kind of silly, since 3 degrees is supported by Model E.

I also believe that applying long-term sensitivities crudely derived from glacial periods is invalid, since we are in an interglacial, and the only ice sheets are near the poles. It seems fairly obvious that the loss of the last bit of ice isn’t going to have the same effect on albedo as the loss of ice closer to the equator during emergence from a glacial period. So – wow. I’m saying Hansen is wrong. Slightly. Oh, no. Hansen’s not stupid. Look what he wrote:

“Note that the 6°C sensitivity for doubled CO2 applies to the Pleistocene. About half of that sensitivity is from the ice sheet albedo feedback. At earlier times in the Cenozoic, between 65 and 35 My BP when there was little ice on the planet, the sensitivity should have been closer to the Charney 3°C sensitivity.”

So yes, long term sensitivity is likely to be higher than Charney sensitivity. But not all that much, and we’re a long way from pinning it down.

Kevin,
My mistake. It was 2008. CRU still has 1998 has the highest at +.56, followed by 2005, +.48. Final numbers for 2010 have not been tabulated, but based on the first 11 months, it is likely to finish third or fourth, (2003).
Long term statistics show that the warming trend has been 0.6C / century, with oscillations above and below the trendline. Nothing observed recently leads me to believe that we have deviated from that trend. I admit that we are current above the trendline, but temperatures have been even higher above the trend in the distant past such that recent events are not outside the realm of variability.

[Response: But why is it trending Dan? Surely that is the question you need to ask before you can decide on what you think is likely to happen in the future? – gavin]

Didactylos,
The problem is that even if we take into account the reduced probability for high values of sensitivity, these values still wind up dominating the risk for the simple reason that the consequences are so much more severe. This is precisely the motivation behind James Annan’s attempts to get rid of the thick high-sensitivity tail by using a Cauchy Prior. This does eliminate the high-end tail, but it is sort of doing the opposite of a Maximum Entropy Prior in that it makes the conclusions of the analysis dependent on details like the location parameter of the Cauchy.

The basic problem is this. We get a climate that most robustly resembles Earth’s with a climate sensitivity of ~3 degrees per doubling. But it’s a whole helluva lot easier to make an Earthlike climate with a higher sensitivity than a lower sensitivity. 2 degrees per doubling is right out. But on the high side a sensitivity of 4.5 degrees per doubling is not all that more appreciably likely than a sensitivity of 6 degrees per doubling.

Now you see why thick-tailed loss distributions drive actuaries and Hedge-Fund managers nuts!

Oh wait… when I first showed up you were not even a moderator here Jim… and I agreed with the RC stance at the time based on their evidence.

[Response: I just went back to your first comments here – and almost all of them were substantive. Yet recently, … not so much. Can we get the old Mack back? – gavin]

[Response: The first comments I remember from you were statements about what research expertise UC Davis does and does not have in different subject areas. I haven’t trusted a thing you’ve said since then quite frankly, and you’ve given me no reason to change my mind.–Jim]

Ray Ladbury: If we wander into the realm of policy, my position is that even the lower end of likely values is quite bad enough, and we desperately need to take decisive and effective steps to cut emissions.

Why worry about tails and uncertainties when exactly the same action is called for by the very likely probabilities?

I’m not saying knowing these further details isn’t valuable – but hopefully you get my drift.

Comment by Didactylos — 14 Jan 2011 @ 9:10 AM
#ccpo: Those may seem scary, but they still seem to be safely within the envelope of IPCC forecasts.

Like heck:

What was Earth’s climate like at the time of past elevated CO2? Consider one example when CO2 was ∼1000 ppmv at ∼35 million years ago (Ma) [2]. Temperature data [5,6] for this time period indicate that tropical to subtropical sea surface temperatures were in the range of 35 to 40 °C (versus present-day temperatures of ∼30 °C) and that sea surface temperatures at polar latitudes in the South Pacific were 20-25 °C (versus modern temperatures of ∼5 °C). The paleogeography of this time was not radically different from present-day geography, so it is difficult to argue that this difference could explain these large differences in temperature. Also, solar physics findings show that the Sun was less luminous by ∼0.4% at that time [7]. Thus, an increase of CO2from ∼300 ppmv to 1000 ppmv warmed the tropics by 5-10 °C and the polar regions by even more (i.e., 15-20 °C).

Show me where the IPCC suggested anything like those conditions. I don’t think you read all the links in the main post I coped from, and I don’t think you are keeping all issues in mind. Take permaculturist’s approach and at all times try to keep all issues in mind. These changes do not happen in isolation, they have follow-on effects in energy production, food production, political stability, social structures, etc., etc., which also amplify the effects and can send things tumbling into chaos.

In my head, new research looks like a web of mycelium spreading our into everything. Like compounding interest or the proverbial butterfly’s wings, small changes in initial conditions create potentially massive changes downstream. As I’ve noted before, as a layman I am not bound to what is provable in my comments. I can allow myself to see what is likely *and* actually speak to it in public. When I start being wrong, I’ll accept your perspective. Since I keep being accurate, perhaps you should consider mine more fully.

And 15-78%? Uncertainty much? It is true that we are dealing with asymmetric uncertainties, but that doesn’t change our best estimate, based on many different methodologies.

Yes, the new data absolutely do change our best estimates. That’s what new data should do. Someone else already addressed the risk assessment issue, but I’ll repeat: insurance is for the long and fat tails, not the first and second deviation. You are arguing the exact opposite of what good risk assessment suggests.

I really don’t understand the arguments that the actual climate sensitivity is likely to lie in the least likely high range any more than I understand those repeated claims we hear that the sensitivity is most likely to be in the least likely low range.

That’s because you buy Charney and the IPCC IV as having accurately set the probabilities. I have never suffered that limitation. Ice, permafrost, clathrates, rates of change all made IPCC IV an excellent out of date report before it was published. Hansen, et al’s., 6C has always seem the more accurate number, and this new research supports that. I don’t really care how you apportion sensitivity – feedbacks, charney, whatever – because I consider it a distinction without a difference outside the lab. It’s a useless conversation for public consumption. The question should be, in terms of public consumption of information, how much total change will we see with a given CO2e?

That’s just not how mathematics work. The likely range is 2-4 degrees

I don’t care what the “likely” range is, I care what the actual range is, and even more so, the worst case because that’s the realm of policy discussions. If our mitigation and adaptation efforts aim for “likely,” the risk of sui-genocidal decisions is far higher than the risks of houses burning down or dying in car accidents. We are talking about a world in which wet bulb conditions become the norm for large areas of the planet. As I noted earlier, those are not butterfly wings, those are pterodactyl wings.

I believe taking only the high estimate from such studies is unjustified, since in reality, the wide spread simply confirms that the true value is likely to be in the narrower range given by more concrete studies.

Except that changes have been at or beyond the high end all along. You are simply ignoring reality in favor of Ivory Tower logic. You might want to keep in mind logic alone can be twisted like a pretzel, so is meaningless in isolation. When I teach young kids about scientific method I stress the importance of letting the data do the talking and especially the incorporation of new data objectively. Faith in middles as bifurcations and dislocations are happening is questionable. For experiments and models – the doing of science – you are correct. For risk assessment and policy discussions, you have it backwards.

ccpo, please also note that Hansen is *not* arguing that Charney sensitivity is 6 degrees. That would be kind of silly, since 3 degrees is supported by Model E.

See previous comment on sensitivity.

I also believe that applying long-term sensitivities crudely derived from glacial periods is invalid, since we are in an interglacial, and the only ice sheets are near the poles. It seems fairly obvious that the loss of the last bit of ice isn’t going to have the same effect on albedo as the loss of ice closer to the equator during emergence from a glacial period.

So? How is this relevant or even logical? There are very potent feedbacks in play now that were not 11 – 20k years ago.

So – wow. I’m saying Hansen is wrong.

I wouldn’t put any money on that.

“Note that the 6°C sensitivity for doubled CO2 applies to the Pleistocene. About half of that sensitivity is from the ice sheet albedo feedback. At earlier times in the Cenozoic, between 65 and 35 My BP when there was little ice on the planet, the sensitivity should have been closer to the Charney 3°C sensitivity.”

So yes, long term sensitivity is likely to be higher than Charney sensitivity. But not all that much

You have offered nothing to support this. To do so you will need to explain virtually all measures of change being at or beyond the worst projections to date, particularly what we are seeing with methane.

and we’re a long way from pinning it down.

I think it is more accurate to say you are a long way from accepting it and that we are some way from proving it.

ccpo: A rise of 5-10 degrees is perfectly plausible. For 1000 ppmv, it makes perfect sense. Two doublings, 3 degrees, that’s 6 degrees. If we take the higher 4.5 degree sensitivity, two doublings equals 9 degrees. So that’s absolutely in line with our current state of understanding, as represented by the IPCC. It also overlaps with the A1F1 model results.

I’m really confused why you are trying to present this as something that hasn’t been considered before. It’s just confirmation of what we know already.

Our present climate observations are absolutely consistent with a Charney sensitivity in the expected range.

With respect to long-term sensitivity, you say “You have offered nothing to support this.” But all I did was actually read the caveats that Hansen wrote, instead of taking him out of context like you did.

You also say “you will need to explain virtually all measures of change being at or beyond the worst projections to date” – but that’s just wrong. Some measures are beyond our estimates. Some aren’t. But that’s beside the point. We won’t clearly see the results of long-term sensitivity for decades, maybe a century or two. Why you even expect to see such observations is a mystery to me, let alone claiming you see them already. Again, your own links explain this.

You keep accusing me of ignoring reality, but you are simply wrong: temperature has not been “at or beyond the worst projections to date”. That’s the measure we have the greatest understanding for, and it is currently completely consistent with our best estimate. (Best estimate, not best case. Don’t confuse the two.) Yes, Arctic ice was low-balled. Methane? That’s generally included in the scenarios, rather than projections. And my reading of WG1 is that observations have come in lower than the scenarios anticipate. Clathrates? Yes, we are observing some bubbling, but it has not caused any significant methane spike. I expect AR5 will go into methane in much more detail.

“As I’ve noted before, as a layman I am not bound to what is provable in my comments”

Now we get to it. To be better than the deniers, we have to hold ourselves to a higher standard. And that means being clear about what we know, and what is speculation.

Didactylos: “Why worry about tails and uncertainties when exactly the same action is called for by the very likely probabilities?”

Well, that’s precisely the issue, isn’t it? Actually, the low end and the high end of even the 90% CL call for dramatically different mixes of mitigation and threat avoidance.

And when you throw in the 5% probability that sensitivity could be above 4.5 degrees per doubling, and the flatness of the tail in this region, then the risk calculus becomes quite complicated. If the sensitivity were actually in this range, the only acceptable strategy would be to put the brakes on CO2…HARD. So, do we ignore this region? Unfortunately, many a hedge fund and insurance company has gone belly up precisely by ignoring such thick tails. Levees have failed and bridges collapsed.

The thing is that there are very few events in climate history that constrain this portion of the curve. It’s much easier to rule out a sensitivity below 2 degrees.

I think more analysis and “publicity” of the sort you alluded to is definitely in order. Obviously my inclination is towards including the economic impacts of =doing= what it would take to get to those scenarios. For example, oil closed at $91 / bbl. How much economic damage are we doing near-term by our dependence on oil, and how much environment damage is in the pipeline long-term by our use of oil.

The absolute worst case scenario, in my opinion, is that we maintain our reliance on fossil fuels, suffer the economic devastation caused by skyrocketing prices, destroy the environment, then don’t have the resources to do anything about it. A bit like “Mad Max”, it seems to me.

7. If all global anomaly increases (there is no such thing as global average temp) were ascribed to GHG increases, sensitivity must be even lower.

8. The case for alarm rests on three doubtful propositions
a. Sensitivity is much higher than 1C due to alleged dominance of positive feedbacks

b. The association of phenomena as sea level rise, arctic sea ice, which depend on many, many factors, of which globally averaged temperature anomaly is not even the most important factor, and to use these changes as evidence for dangerous warming is illogical.

c. This is especially true for sea ice. The over-simplification of climate to a single number, globally averaged temperature anomaly, and a single forcing number, let’s say radiative forcing from CO2, is a gross distortion of what is going on.

With respect to climate sensitivity, GH physics tells us that temp changes at the surface should produce certain change in outward flux of heat, which at the top of the atmosphere is in the form of radiation. It will, in the absence of feedbacks, correspond to a sensitivity of about 1 degree per doubling of CO2. Now, if you have positive feebacks and you go to space and measure the ougoing flux associated with temperature perturbation, you should see less than you would expect without feedbacks, and if you have negative feedbacks you should see more. Now, it turns out that the models when you ask what they calculate, calculate what is consistent with positive feedbacks. If you go to the data, you find the opposite.

More recently there’s been an attempt to measure these fluxes from the surface. You have to understand the flux might be reasonably constant through the atmosphere, but it’s process is different. At the top it’s radiation; at the surface it’s mostly evaporation. And there is a problem that’s been noted for some years. Models predict very little change in evaporation as you warm compared to observations and this can be directly translated into sensitivity. The models’ behavior is consistent with 1.5 to 4.5C per doubling of CO2. The data suggest it’s closer to half the lowest limit.

I mean, one has the problem that the observations when turned to feedbacks rather than specific mechanisms show the opposite. And this isn’t surprising. One speaks of clouds as a kind of peripheral uncertainty, but they are capable… they involve changes in the radiative balance that are, you know, more than a factor of 20 larger than what you get from a doubling of CO2. Now, parenthetically, we might wonder why models that have such a high sensitivity can simulate past behavior if the past behavior is consistent with low sensitivity, and the answer as I think Jerry would point out, is aerosols. Now, you might say there are really aerosols so they cancel some of the greenhouse, but if you check, each model uses a different value. Because they want to adjust their model to look right it’s an adjustable parameter, and the aerosol community (Schwartz, roda(sp?), ) published a paper last year pointing out the uncertainties mean that if you include arbitrary aerosols, you can get any sensitivity you want. That’s hardly reassuring.

Lindzen: zero CO2 equals only 2.5 degrees cooler!

Lindzen: temp devices vastly different, so proportion of record highs and record lows unreliable!!!!!

Most of the commenters here are firm believers in global warming as I am. They argue for it with great knowledge and passion. I am curious what changes they have made in their own lives to reduce their carbon use. I have a feeling some of the most strident believers are doing virtually nothing. I also believe that if they did, they would have a much greater effect on those around them, and would make real strides towards making a difference. When others see what you actually do, rather than what you actually say, you’ll really start to make a difference.I think that can have a multiplier effect.

So maybe, get off the computer today, and go change your light bulbs or put more insulation in your attic? Seriously, I think this could have a HUGE IMPACT. People watch what you DO.

I’m really confused why you are trying to present this as something that hasn’t been considered before. It’s just confirmation of what we know already.

By 2100? Besides, it’s not just the doubling, it’s all the other stuff. That is, we’re going to see the same sorts of changes long before the doubling. That’s really the message. Also, your very point was to de-emphasize the “extreme” possibilities. My point is, they are not the extreme, they are the middle case. 3C is minimum, not a midpoint.

You also say “you will need to explain virtually all measures of change being at or beyond the worst projections to date” – but that’s just wrong.

No, that is exactly my point: The rapidity and degree of changes shows our assumptions are off. Whether that’s due to Charney, not undersanding feedbacks, not being aware of feedbacks, what have you, is irrelevant to my point. We are seeing changes associated with GHG levels we haven’t reached, yet, so forget about the IPCC IV scenarios altogether. Research since then is far more useful, of course.

Some measures are beyond our estimates.
How is what is happening today outside our estimates? Or even be estimates? We are talking observation. My point stands: if you want to warn against alarmism, you better explain why the alarm is sounding, and why so loudly. Explain the melt in Antarctica *now* vs. eventually. Explain thermokarst lakes not only existing, but tripling in size over about 5 years or so *now*, not eventually. Etc. Make that case with a 3C total sensitivity… This is my key point. Even A1F1 doesn’t predict these changes at these rates.

You keep accusing me of ignoring reality

I am saying there is a difference between thinking like a scientist must to maintain credibility and what nature is actually telling us and what the risks are. I leave PC statements to those who are bound. I am not. I can speak to what I see and read, then I can add to it information from energy, economy, socio-political issues to round out what the projections really might be. I.e., reality-based rather than pure scientific method.

but you are simply wrong: temperature has not been “at or beyond the worst projections to date”.

Sorry, should have said CO2. I have a habit of mixing the two in conversation. What is scary, is that at the temps we have so far we see so much change and chaos, no?

Yes, Arctic ice was low-balled. Methane? That’s generally included in the scenarios, rather than projections.And my reading of WG1 is that observations have come in lower than the scenarios anticipate. Clathrates? Yes, we are observing some bubbling, but it has not caused any significant methane spike.

Sub-sea and permafrost melt was included? Nope. I think it’s a fair bet methane will, indeed, be seeing a large rise. The observations certainly suggest this. I was not referring to the current ppb, though the rise from .7-ish to 1.8-ish should scare heck out of us, don’t you think?

Spike? I beg to differ. It was on a ten year plateau till a few years ago. The thermokarst lakes were busy tripling during that time frame. I think you are seeing a spike.

I expect AR5 will go into methane in much more detail.

LOL… one would hope!

“As I’ve noted before, as a layman I am not bound to what is provable in my comments”

Now we get to it. To be better than the deniers, we have to hold ourselves to a higher standard. And that means being clear about what we know, and what is speculation.

UM, nope. There is nothing wrong with Watts, et al., in principle, but the fact they are dishonest. Besides, I am clear what we know vs. what I think. I reject any claim otherwise. I know what Charney is, I just think nature is telling us it’s absolutely not 3C. It’s at the high end. I guarantee you. (Otherwise, real observations don’t make sense vs. scenarios.) Now, note I said I guarantee you, and not that the science guarantees it.

Etc.

Look, you want us all to be circumspect, polite little activists and I think that is suicidal, but, we are on the same side, so let’s not get too caught up in this. Things are changing very quickly, and every new piece of info we get reinforces this. At the end of the day, we’re going to find Charney+ feedbacks is 6C or more, or we’re going to discover something really basic that we don’t understand right now… but that would still be feedbacks… no?… so the situation is dire.

Some of us need to be saying so till the rest of you catch up. (Let me repeat a point made above that all of the non-science issues inform my POV and are feedbacks that are at least as important the climate science itself.)

If I end up being wrong, but we make the changes, well, we’ll have powered down and be living in a much more stable and healthy world, so I can live with that.

Most of the commenters here are firm believers in global warming as I am. They argue for it with great knowledge and passion. I am curious what changes they have made in their own lives to reduce their carbon use. I have a feeling some of the most strident believers are doing virtually nothing. I also believe that if they did, they would have a much greater effect on those around them, and would make real strides towards making a difference. When others see what you actually do, rather than what you actually say, you’ll really start to make a difference.I think that can have a multiplier effect.

So maybe, get off the computer today, and go change your light bulbs or put more insulation in your attic? Seriously, I think this could have a HUGE IMPACT. People watch what you DO.

Re What have you done. My wife and I drive hybrids, we walk to neighboring stores, we have added insulation, we use low energy lights, we keep a/c high and heat low, we recycle extensively, we tinted our windows and installed double pane glass. I also write my congressmen to advocate an increase in the gasoline tax and that I believe in AGW.

Naw..you kind of read my wrong Ray. I think what you are doing is great. Really. Better than me. Am I wrong about everyone else on here? Do you have personal knowledge of the habits of all the commenters?

This wasn’t meant to be a fight, but rather encouragement for people. I don’t think I’m your enemy.

#191 Doug. What do you say to a vegan, who lives in a country where electricity is generated without carbon emissions? Buy one of these: http://www.hydrogencarsnow.com/bmw-hydrogen7.htm
Joking aside, what is the carbon footprint of converting the world’s car-fleet to hydrogen?

We’ve established you were mistaken about temperature. You are also mistaken about CO2, which has been rising perfectly in accordance with the scenarios (how could it not – they cover all likely eventualities).

So, let’s follow this through: “The rapidity and degree of changes shows our assumptions are off.” But you were wrong about that. The opposite is true. The neat match between reality and models shows us that our assumptions are spot on, or close enough to be going on with.

Doug, Please forgive my accusation, but yes, I do know what many of the commenters are doing. Tamino had a post awhile back where he asked just this. I, myself, carpool with a disabled woman. I try to grow as much of my own food as possible. My wife and I have planted a couple hundred trees on our property. Furry Catherder is just about carbon neutral. You’ll find plenty of early adopters of hybrid vehicles, efficient lighting…. I think you really should investigate before making accusations that the folks here are less than committed. They are.

Let’s not jump the gun too much on how alarming “new” climate sensitivity estimates are. The Kiehl article in Science is interesting but let’s keep in mind that he’s comparing snapshots in time over a range of tens of millions of years, and it’s not self-evident that CO2/solar are the only significant forcings relevant for a good comparison, or that you can easily extrapolate the same sensitivity to the future. There’s also a lot of ways the proxies for temperature and CO2 can be off. I don’t really think the spatial structure of land and sea surface temperatures in deep time climates is settled at the present.

Also keep in mind that while the public may not be interested in what the “Charney sensitivity” is, you do have to know what it refers to if you’re going to claim it’s different than the ‘actual’ sensitivity. For that matter, what exactly does the ‘actual sensitivity’ refer to? The paleoclimate inferences derived from the Kiehl article is most useful for understanding the very long-term response to a perturbed climate, like I discussed toward the end in part 1 of my post on feedbacks and what several scientists are now including in the Earth system sensitivity response. The long-term outlook is the focus of a number of recent articles, a key resource is the 2010 Climate Stabilization Targets: Emissions, Concentrations, and Impacts over Decades to Millennia report from NAS. While this is important, and can be the subject of many debates on cost-benefit analysis and economics, the transient climate response is much more useful as a gauge for what to expect in the coming century.